Paper trimmer



Oct. 2, 1956 w. MCDONOUGH ETAL 2,765,037

PAPER TRIMMER Filed Sept. 28, 1953 3 WWW J I 1M5 m pm 7 F 4 Ww United States Patent 2,765,037 PAPER TRIMMER Will D. McDonough, Mill Valley, and Joseph F. Ennis, Tiburon Highway, Calif.

Applicah'on September 28, 1953, Serial No. 382,652

6 Claims. (Cl. 16477) This invention relates to and in general has for its object the provision of a paper trimmer of such character that the wear of the cutting edge of the device is reduced to a minimum and is self-sharpening and such that during the cutting operation, there is no tendency for the paper to become misaligned.

In the design and manufacture of most paper trimmers now on the market, a deliberate attempt is made to obtain a shearing action between the cutting edge of the trim board and the cutting knife or disc associated therewith. This is done by slightly inclining the cutting edge of the knife or disc with respect to the cutting edge of the trim board and results in undue wear of these edges and a tendency to misalign the paper being cut.

More specifically the object of this invention is the provision of a paper trimmer wherein a cutting disc having a hollow ground cutting edge is made to traverse the cutting edge of a trim board always in parallelism therewith and with no shearing action relative thereto.

More specifically it is the object of this invention to provide a paper trimmer comprising a trim board having a cutting edge and on which is mounted a track in parallelism with said cutting edge, sa-id track mounting a car riage and said carriage mounting a cutting disc having a two point contact with said cutting edge and at least a one point contact with a rolier support by said carriage about the axis of said disc and generally opposite said two point contact whereby said disc is always maintained in parallelism with the trim board cutting edge.

The invention pcssesses other advantageous features, some of which, with the foregoing, will be set forth at length in the following description where that form of the invention which has been selected for illustration in the drawings accompanying and forming a part of the present specification, is outlined in full. In said drawings, one form of the invention is shown, but it is to be understood that it is not limited to such form, since the invention as set forth in the claims may be embodied in other forms. 5

Referring to the drawings:

Fig. 1 is a perspective view of a paper trimmer embodying the objects of our invention.

Fig. 2 is an enlarged perspective detail of the track, carriage, rotary cutter and trim board cutting edge of the device.

Fig. 3 is a right-hand end view of the structure illus- 80 trated in Fig. 2.

As shown in these figures, the objects of our invention have been embodied in a trim board 1 of conventional construction and provided with a metal strip insert 2 having a cutting edge 3. Fastened to the trim board 1 at one end thereof is a pair of opposed brackets 4 and 5 and supported by these brackets is an I-beam 6 serving as a carriage track, the lower end of this I-beam being formed with a rack 7. Mounted on the I-beam 6 is a carriage generally designated by the reference numeral C including a pair of opposed parallel plates 8 and 9 held in spaced relation by pins 11 and 12. Journaled on selected pins 12 are rollers 13 arranged to roll over the upper face of the upper web of the I-beam 6. Journaled on pins 14 and fastened to the opposed plates 8 and 9 are rollers 15 arranged to engage the lower face of the upper web of the I-beam 6. As a result of this construction, the carriage C is free to traverse the beam 6 in strict parallelism therewith.

Journaled in the two plates 8 and 9 beneath the I- beam 6 is a pin 16 and fixed to this pin within the confines of the two plates 8 and 9 and in mesh with the rack 7 is a gear 17. Also journaled in the plates 8 and 9 somewhat beneath and to one side of the pin 16 is a shaft 18 and keyed or otherwise afiixed to this shaft is a gear 19 in mesh with the gear 17. The inner or left-hand end 21 of the shaft 18 as viewed in Fig. 3 is formed of a reduced diameter. Mounted over the end 21 is a washer 22 and keyed to the end 21 in engagement with the washer 22 is a cutting disc 23 having a hollow ground peripheral edge 24. Threaded to the end 21 is a screw 25 serving to hold the cutting disc 23 in place and at the same time permit the disc to wobble slightly.

As a result of this construction, it will be seen that if the carriage is made to traverse the beam 6, the gear 17 will be caused to rotate and since this gear is in mesh with the gear 19, this gear, the shaft 18 and the cutting disc 23 will also be caused to rotate.

The shaft 18 is so journ-aled in the plates 8 and 9 that it is free to move axially in and out to thus permit the cutting edge of the disc 23 to be brought into engagement with the cutting edge 3 of the trim board. Mounted on the shaft 18 is a biasing spring 26, the ends of which abut the inner face of the plate 7 and the outer face of the gear 19. Since the gear 19 is fixed to the shaft 18, the spring 26 serves to urge the shaft 18 to the left as viewed in Fig. 3 and consequently maintain the cutting edge of the disc in contact with the trim board cutting edge 3.

As a result of this construction, the cutting disc 23, since it is free to wobble on the end of the shaft 18, would be urged to an inclined position out of parallelism with a vertical plane passing through the cutting edge 3. To obviate this condition and to always maintain the cutting disc 23 in the vertical pl-ane of the cutting edge 3, a bracket 27 is mounted on the plate 8 by a screw 28 and journaled on the outer free end of this bracket is a roller 29 arranged to contact the upper inner periphery of the cutting disc 23 and to maintain this edge in the vertical plane of the cutting edge 3. As shown in Figs. 2 and 3, the cutting disc 23 overhangs the cutting edge 3 so that the cutting edge of the disc contacts the cutting edge 3 of the trim board at two spaced points, these points, as clearly appears from Fig. 2, being located at the ends of a cord of the cutting disc 23. The roller 29 serves as a third point of support for the cutting disc 23, this point being diametrically opposed with respect to the two points of contact between the disc 23 and the cutting edge 3. This arrangement therefore insures that the cutting disc 23 is always resiliently maintained in the vertical plane of the trim board cutting edge 3 thereby to obviate any shearing action between the cutting edge of the disc 23 and the trim board cutting edge 3. This in turn minimizes the wear on both the cutting edge 3 and the hollow ground cutting edge 24 of the disc 23. Since the cutting edge 24 of the disc 23 is hollow ground, it can be sharpened by merely causing the carriage C to traverse the I-beam 6. Also as a result of the fact that all shearing action between the disc 23 and the trim board cutting edge 3 has been eliminated, there is no tendency during the operation of this device to misalign the paper being cut.

Optionally and for safety purposes and as shown in Fig. l, the exposed edges of the cutting disc 23 may be inclosed within a guard casing 31 mounted on the carriage and aflixed thereto in any suitable manner.

Having thus described our invention, what we claim and desire to secure by Letters Patent is as follows:

1. A paper trimmer comprising: a trim board provided with a cutting edge; a track supported by said board above and in parallelism with ,said cutting edge; a carriage arranged to traverse said track; a shaft journaled in said carriage for rotation on a fixed axis relative to said can riage transverse to said track; a cutting disc fixed to the inner end of said shaft, said disc being free to wobble on said shaft but fixed against axial movement relative thereto, and the diameter of said disc and the position of said shaft being such that the lower portion of said disc overhangs said cutting edge and engages said cutting edge at two points; an inwardly extending bracket mounted on the inner face of said carriage over said disc; and a roller mounted on said bracket in engagement with the outer periphery of said disc, said roller serving to maintain said disc in the vertical plane of said cutting edge.

2. A paper trimmer such as defined in claim 1, wherein said shaft is spring biased inwardly toward said trim board.

3. A paper trimmer such as defined in claim 1 wherein the cutting edge of said disc is hollow ground.

4. A paper trimmer comprising: a trim board provided with a cutting edge; a track supported by said board in parallelism with said cutting edge; a carriage arranged to traverse said track; a cutting disc supporting member mounted on said carriage for limited movement transverse to said cutting edge; a cutting disc mounted on said supporting member in vertical alignment with said cutting edge, said disc being free to wobble on said supporting member but fixed against axial movement relative thereto, the diameter of said disc and the location of said supporting member being such that the lower portion of said disc overhangs said cutting edge and engages said cutting edge at two points; a bracket mounted on said carriage and extending over said disc; and a roller mounted on said bracket in engagement with the outer periphery of said disc, said roller serving to maintain said disc in the vertical plane of said cutting edge.

5. A paper trimmer such as defined in claim 4 wherein said shaft is spring biased inwardly towards said trim board.

6. A paper trimmer such as defined in claim 4 wherein the cutting edge of said disc is hollow ground.

References Cited in the file of this patent UNITED STATES PATENTS 387,621 Clarke Aug. 14, 1888 511,563 Thyll Dec. 26, 1893 556,369 Price Mar. 17, 1896 733,511 Ridgely July 14, 1903 804,520 Colthar Nov. 14, 1905 1,541,155 Kroes'en June 9, 1925 2,191,148 Perbal Feb. 20, 1940 

